Out of the box, rxvt-unicode is not too pleasant to look at. Some understanding of Xresources is required for updating its appearance. That being said, the experience of customizing it can be very rewarding.

If a character in a backup font is wider than the base font, urxvt substitutes the non-displayable character. A large letter space will show the wide characters, but the result is not reasonably spaced. There is a patch from 2014 that the urxvt maintainer will not merge.

There are tons of customizations you can make: from adding colors to text, turning backgrounds transparent, setting the size to be "maximized", toggling scrollbar on and off, adjusting orientation/borders/animation, etc.

The default configuration may have some annoying behaviors (that can be removed by changing the default config). Such include asking for confirmation when reusing an existing window or when starting the terminal to launch a specific command.

Thumbnails, pictures, and videos can all be rendered in-terminal, based on the directory listing or mouse interactions. For instance, using "ls" on a picture folder will produce a list of thumbnails instead of only the filenames.

Suppose you have a dark background with a light cursor and light foreground color: the light cursor will cover up whatever character it is on, so that you cannot read it. There is no option to set the foreground color for the character under the cursor to what is normally the background color. Such...

Termite supports a command mode which is very useful if you prefer to use Vim-like keybindings. It takes inspiration from Vim, one of the most popular text editors, so someone who is used to Vim's commands will find themselves at home.

After (re)booting the system, Guake does not boot automatically. You need to open the application and then press the key to make it drop down which is a bit annoying when you want to get started quickly and don't want to press two different keys just to open the terminal.

ROXTerm includes a configuration manager which can easily be run by selecting Configure... in the terminal's menu, or by simply running roxterm-config. You can then easily swap configuration files with other users, manage profiles, and customize things like color schemes or keyboard shortcuts.

Yakuake is a drop-down terminal. This means that you can press, for example, F12, and it slides downward from the top edge of the screen. After you are done with it, you can then hit F12 again and it slides back on top.

While not an issue if using KDE, when trying to use this terminal in other desktop environments or window managers, there will be a large amount of dependencies tied to the app. This makes for a large install size. For those trying to keep their desktop lean, this may be an issue.

Xiki uses some GUI concepts on top of shell. For example, commands can have nested menus and these menus are just text indented by two spaces. You can also either use the mouse or the keyboard to navigate or issue commands.